To the Editors:
The classic rubella syndrome is characterised by the combination of cardiac, ocular and hearing defects, although infection and damage can occur in every organ system. Since the advent of effective vaccination, the number of new cases of congenital rubella has plummeted.
The cardiac abnormality most frequently found in rubella syndrome is a combination of branch pulmonary artery stenosis and patent ductus arteriosus, though isolated branch pulmonary artery stenosis is twice as common as isolated patent ductus arteriosus [1]. However, a wide variety of cardiac malformations may be produced, such as ventricular and atrial septal defects, stenosis of the pulmonary and aortic valves, Fallot's tetralogy, coarctation of the aorta, tricuspid atresia and transposition of the great vessels. Localised pulmonary arterial stenosis may appear in one of three main forms. First, there may be isolated or multiple stenoses of the pulmonary arteries themselves. Secondly, there may be involvement of the bifurcation of the pulmonary trunk, the so-called coarctation of the pulmonary artery. Thirdly, stenosis may be due to a membrane situated immediately above the pulmonary valve [2]. Why rubella virus has such a predilection for the structure of the embryological sixth dorsal arch is not known, but it is certainly true that finding of patent ductus arteriosus and pulmonary artery stenosis far exceed those of valvular and septal defects in this infection [3].
We present the case of 17-yr-old girl with congenital rubella syndrome, recurrent pneumonia in childhood and a New York Heart Association functional class I–II/IV. Physical examination included a low-frequency systolic ejection murmur in the left infraclavicular region. The 12-lead ECG was normal and the transthoracic echocardiogram showed normal pulmonary artery pressure with absence of a normal origin of the left pulmonary artery. 99mTc-MAA (macroaggregates of albumin) lung scintigraphy demonstrated moderate hypoperfusion of the left lung and the computed tomography angiography showed an anomalous left pulmonary artery arising from the posterior portion of the right pulmonary artery and running between the trachea and the oesophagus to reach the left hilum (fig. 1). Also, mild compression of the main stem and the left bronchi were seen. No associated anomalies of the tracheobronchial tree were found.
An anomalous origin of the left pulmonary artery, i.e. which arises from the right pulmonary artery and courses to the left, passing between the trachea and oesophagus, is also known as pulmonary artery sling, and is a rare congenital condition probably due to involution of the proximal left sixth arch [4]. Its incidence is 3–6% of all aortic arch anomalies, though it has never been described in the congenital rubella syndrome. Patients affected by pulmonary artery sling may be classified generally into two groups: one with a normal bronchial pattern and the other with one or more malformations of the bronchotracheal tree, such as stenosis of a long segment of the trachea or absence of the pars membranacea, as well as cardiovascular abnormalities [5]. In the latter group, mortality and morbidity are high during infancy because compression of the trachea and right main stem bronchus produces severe respiratory distress within the first year of life. However, asymptomatic pulmonary artery slings are typically diagnosed incidentally in adolescence or adulthood.
Pulmonary artery sling can be repaired in infancy with low operative mortality and excellent long-term patency of the left pulmonary artery, by dividing the left pulmonary artery and implanting it into the main pulmonary artery anterior to the trachea [6]. In contrast to symptomatic patients, the prognosis for asymptomatic patients is excellent and surgical intervention is not indicated.
Footnotes
Statement of Interest
None declared.
- ©ERS 2012